Recherches sur Oidiopsis taurica. 



par Et. FOEX. 



(Planches XXXIV, XXXV, XXXVI, XXXVII et XXXVIII). 



L'espèce Erysiphe taurica a été créée par Léveillb [5], qui 

 en donne la diagnose suivante : 



Erysiphe taurica Lev. — Bifrons. Mycelio floccoso evanido 

 vel persistente. Conceptaculis gregariis aut sparsis, hemisphe- 

 ricis, magnis, demum depressis. Sporangiis 8-30 in pedicellum 

 longiusculum productis. Appendiculis cum mycelio interxtis. 



Léveillé signale comme hôte : Zygophyllum Fabago, 

 Peganum Hamala, Dorycnium herbaceum, Inula nervosa, 

 Cirsiurn eryophorum, plantes originaire de Tauride ; Aplo- 

 taxis, de l'Himalaya ; Carlino, co/\//mbosa,de France méridio- 

 nale. 



Salmon en donne une description étendue : 



« Ampliigenous, often covering the whole plant ; mycélium 

 usually persistent, effused, densely compacted, tomentose- 

 membranaceous, or crustaceous, usually white, rarely pale 

 buff in places, sometimes, however, wholly evanescent ; peri- 

 thecia scattered or gregarious, usually more or less immersed 

 in the persistent mycélium, large, 135-240 ;j. in diameter, 

 usually about 200 [a, soon becoming concave, cells obscure ; 

 appendages usually very numerous, densely interwoven, rather 

 short, more or less vaguely branched, colorless or brown, 

 sometimes very short or even obsolète ; asci 7-38, usually 

 about 20, large from narrowly cylindrical to ovate, usually 

 longly pedicellate, 75-110 (usually about 90) X 18-40 p. ; spores 

 2, large, viarable in size, usually about 32 x 18 (/., but varying 

 from 28-40 X 14-22 a, sometimes slightly curved. 



Hosts. — Acanthophyllum gland ulosum, Alhagi camelo- 

 rum, A. maurorum, Althsea ficifolia, A. kurdica. Arctium 



